1. Field of the Invention
The present invention relates to a low power AC/DC and DC/DC converter. In particular, the invention relates to an AC/DC and DC/DC converter having a circuit topology of the buck (or step down or forward) type or of the buck-boost (or step up/down or flyback) type.
2. Description of the Related Art
As is known, AC/DC and DC/DC converters having a circuit topology of the buck type or of the buck-boost type use inductive components the charging and discharging of which are controlled by switches that switch between a saturation and an inhibition condition (ON/OFF).
For a more detailed treatment of AC/DC and DC/DC converters of the type referred to above, see, for example, J. G. Kassakian, M. F. Schlecht, G. C. Verghese xe2x80x9cPrinciples of Power Electronics,xe2x80x9d Addison Wesley.
In certain applications, AC/DC and DC/DC converters having dual outputs are required, i.e., converters able to supply both a positive voltage and a negative voltage. For this purpose (see, for example, the standard buck converter of FIG. 1), an inductor 1 belonging to an output filter 2 has a first winding 1a connected to a first output 3 and a second winding 1b, appropriately coupled to the first winding 1a, connected to a second output 4 through a second output filter 5.
The above solution is adequate in the case of converters with a high output current, where wound inductors are used; however, it is not convenient in the case of converters supplying a low output current, where the inductor is formed by an axial inductor insulated in lacquer, that has a low cost and small dimensions.
An embodiment of the present invention provides a converter that is able to supply a dual output without requiring the use of a double winding inductor. An inductor that can be used in the case of a non-insulated converter.
In one embodiment of the present invention there is provided a converter comprising a first input receiving an input voltage, a first output supplying a first output voltage having a first sign, a second output supplying a second output voltage having a second sign opposite to the first sign, a controlled switch connected between the first input and a first intermediate node, a first component connected between the first intermediate node and the first output, and a second component connected between the first intermediate node and a second intermediate node, one of the first and second components comprising an inductive element, and another of the first and second components comprising a unidirectional current conducting element, the converter being a dual voltage generating circuit connected between the second intermediate node and the second output.